Resinous condensation products of allylated phenolic resins and epoxy resins are known in the art. Thus, U.S. Pat. No. 3,291,770 discloses resins which are the acid catalyzed condensation products of certain ethoxyline resins with allylated polyalkylol phenols or with mixed allylated and non-allylated phenols. These resins, when dissolved in organic solvents, provide excellent coatings, especially for metal substrates. These coatings adhere well to metals and remain flexible, thereby facilitating fabrication of the pre-coated metal into various shapes such as cans, containers, and the like.
However, the prior art methods of producing these resins, as taught in U.S. Pat. No. 3,291,770, are limited to condensing certain ethoxyline resins with allylated polyalkyl phenols in the presence of an acid catalyst and an aliphatic alcohol, wherein the presence of the aliphatic alcohol during the condensation reaction is critical. It would be advantageous to be able to produce these resins by a method wherein the presence of the aliphatic alcohol during the condensation reaction is not necessary. It has now been discovered that these resins can be produced by the acid catalyzed condensation of an ethoxyline resin with an allylated polyalkylol phenol without the presence of the aliphatic alcohol during the condensation reaction.
The organic solvent soluble thermosetting resins produced by the method of the instant invention provide a significant advance over the resins of the prior art wherein cold blends of allylated and non-allylated phenolic and epoxy or ethoxyline resins are cured to provide protective coatings. In coatings made by such prior art cold blending techniques the phenolic and ethoxyline resins are not reacted with each other until the blend of these resins is cured by the application of heat to form insoluble set products. The method of this invention now provides a thermosetting organic solvent soluble resin having both ethoxyline and phenolic components which is formed by the condensation of an allylated phenol component and an ethoxyline resin component. The resulting product is stable and has a long shelf life, and when dissolved in a suitable organic solvent provides a curable coating composition which upon baking produces protective coatings.